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AUTUMN 2016 ISSUE
LIVESTOCK MATTERS
12
POST-MORTEMS
In a high percentage of PM cases, the cause of death can be determined from gross examination alone
without needing laboratory tests
Diagnosing the cause of death of one animal,
can provide the information to protect the health
and performance of the rest of the flock/herd
Below are some summaries of recent findings from post-mortem examinations collected
through the XLVets scheme.
Example cases
An adult lactating dairy cow was found
dead with no previous history of ill health.
Post-mortem examination revealed multiple
lesions on the heart valves and chronic
scar tissue, and adhesions between
reticulum and lower left abdominal wall.
There was a small abscess in the wall of
the reticulum which contained a 5cm
length of sharp wire. A magnet in the
reticulum was covered in wire and metal
shards.
Tyre wire disease was listed as the fourth
most common diagnosis at post-mortem of
adult dairy cows in a retrospective study
carried out by SAC Consulting. On this
farm, the examining vet commented that
the magnet seemed ‘full’ with metal and
that administering another magnet to older
animals should be considered.
Case 1:
Case 2:
A three-year-old dairy cow in late
gestation
was presented for examination
with generalised weakness and muscle
tremors. The cow did not respond to
treatment with magnesium sulphate and
died soon after.
Post-mortem examination revealed a
uterine tear and the calf free in the
abdomen. This is likely to have
happened from a fall or trauma to
the abdomen.
Case 3:
A carcase of an eight-week-old mule
lamb
was found to have a faecal worm
egg count of Nematodirus of 1,650
eggs per gram. Fifteen lambs in a group
of 80 were scouring. They had not
received any anthelmintic treatment this
season.
There were a number of cases of
Nematodirus diagnosed at post-mortem,
during May and June. In this case the
farmer was advised to worm the group
with a benzimadazole product and
submit a faeces sample for analysis
10-14 days later to check the efficacy
of the anthelmintic.
A six-week-old male Texel cross lamb
was recumbent for 3 days before death
despite treatment with antibiotic.
On post-mortem examination, pericarditis
was found to be the cause of death –
this is swelling of the fluid-filled sac that
surrounds the heart. There had been a high
lamb mortality rate in the flock this year and
a number of post-mortem examinations had
been carried out. Pasteurellosis had been
the cause of death in the majority of cases.
Pericarditis in this case could be attributed
to pasteurellosis.
Although ewes had been vaccinated with a
multivalent clostridial vaccine 4-6 weeks
pre-lambing, the passive antibody transfer
would not have provided long-lasting
protection for the culprit bacterium in this
case. So following the results of the PMs,
it was recommended that next year, lambs
be vaccinated at 3 weeks of age.
Case 4:
Case 5:
A five-day-old castrated male lamb
was
found dead.
Lee-Anne explains: ‘It took me less than ten
minutes to discover it had a ruptured bladder,
and damaged kidneys. The cause was found
to be the castration ring, which when applied
had trapped part of the lamb’s urethra, and
it had been unable to pass urine. The farmer
had been preparing to administer antibiotic
treatments to all lambs thinking it was a
disease, but in fact, it was a practical
management error.
Post-mortems:
•
Can sometimes be the only way to
reach a correct diagnosis
•
Can lead to a more targeted
approach to treatment and prevention
•
Can save money in the long term
•
The fresher, the better!